Printing machine plate lock-up



July 26, 1960 c. A. HARLESS 2,946,282

PRINTING MACHINE PLATE LOCK-UP Filed April 20, 1954 2 Sheets-Sheet 1 July 26, 1960 c. A. HARLESS 2,946,282

PRINTING MACHINE PLATE LOCK-UP Filed April 20, 1954 2 Sheets-Sheet 2 5 2 EVENTOR.

2,946,282 I PRINTING MAC PLATE LOCK-UP Charles A. Harless, Riverside, Conn., assignor to R. Hoe 8: Co., Inc, New York, N.Y., a corporation of New York Filed Apr. 20, 1954, Ser. No. 424,364

7 Claims. (Cl. 101-4151) This invention relates to plate lock ups for web printing machines, and more particularly to lock ups for relatively thin plates such as are used in offset printing and which are required to be held and tensioned on a plate or printing cylinder.

In such machines it is desirable to have only a small gap in the plate surface at the point of attachment of its ends to the cylinder, the plate must be firmly held under as even tension as possible and the operation of inserting and removing a plate should be as simple and quick as possible. The general object of the present invention is to provide an improved plate lock up mechanism fulfilling these requirements to the fullest extent.

A lock up embodying the invention in a preferred form will now be described in detail with reference to the accompanying drawing, and the features forming the invention will then be pointed out in the appended claims.

In the drawings: I

Fig. 1 is a diagrammatic plan view of one end of a cylinder embodying the invention in a preferred form;

Fig. 2 is an enlarged cross section through the plate holding mechanism of the cylinder of Pig. 1 as viewed looking toward the left;

Fig. 3 is a view similar to Fig. 2, but showing the parts in a difierent position;

Fig. 4 is a plan view to about half the scale of Fig. 2, showing associated support elements as broken away to the planes 44 and 4'4 of Fig. 2 to the left and right, respectively;

Fig. 5 is a detail end elevation of a plate end clamp assembly used for holding the plate end.

The cylinder may be of any desired size and construction generally. It is formed with a generally rectangular channel 11 for holding the plate operating mechanism, and with a bore 12 communicating with this channel to one side thereof and accommodating the plate lock up operating shaft 13.

The operating parts comprise a block 14 fitting in the V groove and held therein by screws 15, this block having a convex arcuate surface 16 forming part of the cylinder surface and a concave arcuate or cylindrical surface 17 upon which rotates one or more movable lock up members 18 each formed with a corresponding cylindrical bearing surface 19. On wide machines several short lock up members 18 may be used instead of one long member. Concentric with the surfaces 17 and 19 is a concave cylindrical surface 20 of the members 18 which cooperates with the cylindrical surface 21 of a bar 22. The bar 22 is fixed to a support member or block 23 by screws 24, the block 23 being fixed in the channel 11 by screws 25 and further held therein by a shoulder 26, which fits under an overhanging ledge 27 formed on one wall of the channel 11. The bar 22 is formed at one side with a groove having a generally radial wall 28 for a purpose described below. The block 23 has a cylindrical surface 29 forming part of the cylinder periphery and ending in a rounded nose 30 around which the plate passes. Inwardly of the rounded edge or nose 30 the block 23 is atent O 'ice formed with a flat section 31 and with a shoulder 32 at right angles thereto. A plate end clamp designated generally at 33 fits against the shoulder 32 and the wall 28 as later described. Each lock up member 18 is formed with generally similar arrangements for holding a second end clamp member designated generally at 34, and these include the rounded edge 35 and a flat surface 36, the end clamp member 34 sitting against the latter.

The plate P is a generally rectangular metal sheet, as usual, to the ends of which are attached the plate end clamps 33 and 34. Each end of the plate proper is clamped between bars and 41, fastened together. by screws 42, so as to firmly grip the plate. Bar 41 is fo'rmed with a bevel surface 43 shown as being at about 30 to the plate, with the right angle shoulder 44 and with a flat 45. Bar 40 is formed with bevels 46 at the same angle to the plate as bevel 43 or a degree or'two less, and is flat and parallel to the plate between these bevels. The end clamp 33 at one end of the plate and the end clamp 34 at the other, have their screws 42 opposite each other, when in locked up position, and the clearance between the screw heads is reduced as shown, to a point where it is impossible for either screw to loosen materially, since the screws are practically in contact.

In locking up the plate, the plate end clamps 33 and 34 are placed as shown in Fig. 3, with the shoulders 44 hooked or engaged together. The natural elasticity of the plate which is bent as indicated at P1 serves to hold the end clamps 33 and 34 in engagement as shown. The locking up is accomplished (by mechanism later de scribed) by rotating the member 18 (clockwise) from the position of Fig. 3 to that of Fig. 2. The rounded gap edge 35 engages the plate P at about the location of P1, gradually forces it into its final position and the surface 36 engages the upper or outer bevel 46 on the clamp 34' forcing this element to'ward the In the final position, as shown in Fig. 2, the clamp 34 is firmly wedged in place between the surface 36 and the cooperating clamp 33 and this element, in turn, is firmly forced against shoulder 32 and flat surface 28. An exceptionally simple and reliable plate lock up is thus provided. It will be noted that the plate where it passes over the rounded gap edges 30 and 35 is subjected to little or no abrasion. The only frictional movement around the gap edge 30 is that involved in the tightening of the plate around the cylinder circumference. With respect to the gap edge 35, this edge initially engages the plate at substantially the same place as it engages it in locked up position, so there is practically no bending movement of the plate. It thus becomes possible to apply considerable tension to the plate around the cylinder without tensioning it excessively adjacent its edges where it passes into the cylinder gap.

The means for rotating the members 18 comprise the shaft 13 previously referred to. At intervals along the length of this shaft, it is provided with bearing bushings or sleeves 50, between each pair of which there is located cooperating clamp 33.

- a split collar or screw clamp 51 held together by screws or bolts 52 and upon which is formed a fork 53 carrying a pin 54 on which is pivotally mounted a pair of chain side links or plates 55, the other ends of which are pivotally attached to a member 18, by means of a pin 56 passing through a block 57 which is fixed to the member 18 by screw 58. A spring 60 may pass around the pin 54 and engage against shaft 13 as indicated for the purpose of taking up slack or backlash in this mechanism and insuring equal distribution of the turning force on the members 18. The end of operating shaft 13 is provided with a socket 61 (Fig. 1) to take a wrench for turning the shaft and may be held in locked up position by means of a spring detent or other catch member 3 62. The cylinder end is closed ofi by filler block 63 and bearer 64.

By using a plate registering table such as is disclosed in Patent 2,234,170 the plate end clamps 33 and 34 may be accurately positioned and secured to each'end' offa printing plate, and the" plate 'then bent at thefiprope'r places, so that when it is locked up on the cylinder it will fit perfectly and be properly tnsioned.

' What is claimed is:

1. In'a printing machine plate cylinder for flexible plates and having a gap for receiving the plate ends, plate holding mechanism comprising a plate holding member forming an edge of the cylinder gap and an adjacent part of the cylinder plate supporting surface, means mounting the member for angular movement between plate holding position and a retracted gap opening position, the plate holding member having a plate end engaging surface which is substantially smooth and which diverges inwardly from a radial plane including the said gap edge when in plate holding position to hold a plate end by wedging action, a plate having an end in'the gap and free to move therein and cooperating plate holding means holding the plate end against the said substantially smooth surface and thereby wedging it radially inward. and holding it in the cylinder.

2. Plate holding mechanism according to claim 1, in which the means mounting the plate holding member comprises a shaft extending its length and the plate holding member has a concave cylindrical surface engaging the said shaft.

3. Plate holding mechanism according to claim 2, in which the said shaft has a groove for accommodating the opposite end of a plate;

4. Plate holding mechanism according to claim 3, in which the concave cylindrical surface and substantially smooth plate engaging surface of the plate engaging member are adjacent.

5. A printing machine plate cylinder comprising, in combination, a cylinder having a gap, a plate holding member forming one edge of the gap and rotatively movable between plate holding position and a retracted gap opening position, a cooperating plate holding member having a ledge for engaging a plate end fitting to hold it radially of the cylinder, the first said plate holding member having a substantially smooth plate end engaging surface, and a flexible plate having end fittings formed to interlock when one end fitting is placed under the ledge, the plate is wrapped around the cylinder and the other end fitting is placed against it, whereby the plate may first be temporarily attached to the cylinder by interlocking of the said end fittings and then secured thereto by rotating the first mentioned plate holding member to wedge the end fittings together.

6. A printing machine plate cylinder according to claim 5, in which a rotative axis of the first said plate holding member is located in a radial plane spaced from the gap edge of the said member in the direction of the gap, whereby the said member is kept within the profile of the cylinder in its movement between plate engaging position and retracted gap opening position.

7. A printing machine plate cylinder according to claim 6, in which the said rotative axis is located to bring the said gap edge into pressure contact with the plate along substantially the same line as the line of engagement in plate holding position.

References Cited in the file of this patent UNITED STATES PATENTS 1,582,390 Evans Apr. 27, 1926 1,795,700 Baldwin Mar. 10, 1931 1,795,702 Barton Mar. 10, 1931 2,051,858 Huck et a1 Aug. 25, 1936 2,056,205 OHara Oct. 6, 1936 2,056,991 Tomlin Oct. 13, 1936 2,105,452 Busk Ian. 11, 1938 2,157,621 Neilson May 9, 1939 2,409,536 Braunworth Oct. 15, 1946 2,621,592 Faeber Dec. 16, 19 52 2,641,183 Boyajean v June 9, 1953 FOREIGN PATENTS 617,936 Germany Aug. 30, 1935 1,044,012 France June 17, 1953 

